A firestop collar arranged around pipes or cables comprises intumescent material that expands upon exposure to heat, closing off the penetration as tightly as possible so as to prevent propagation of the fire. Depending on the diameter of the penetration, the firestop collar can be arranged on an outer end of the penetration, for example, on the wall or floor/ceiling, or else directly in the penetration. When the firestop collar is arranged at the entrance to the penetration, it is normally fastened to the wall or floor/ceiling by means of brackets.
This situation is shown by way of an example in FIG. 1. A wall 2 has a penetration 4 through which a pipe 6 runs that extends along the longitudinal axis A. A firestop collar 7 which is, for instance, a fabric collar made of an intumescent material 8 wrapped with a fabric 9 surrounds the pipe 6 at the entrance of the penetration 4 in the circumferential direction. The firestop collar 7 is fastened by means of a bracket 10. The bracket is fastened to the wall 2 with a screw 12 and it comprises a fastening section 14 that is in contact with the wall 2 as well as a support section 16 that is in contact with the firestop collar 7.
FIG. 2 shows a schematic top view of a firestop collar 7 mounted on several brackets 10. The support sections 16 of the bracket 10 are additionally provided with claws 18 that affix the firestop collar 7. In case of fire, the intumescent material 8 expands in the direction of the pipe 6 (indicated by arrows). This prior-art arrangement, however, entails the problem that some of the intumescent material 8 widens in the axial direction (that is to say, essentially parallel to the longitudinal axis A of the pipe 6) and is squeezed out at the opening of the penetration 4 on the wall side. As a result, intumescent material is lost and is then not available to close off the penetration 4. A correspondingly large quantity of intumescent material 8 is normally employed in order to remedy this problem.